To determine when exactly the holy month will begin, Muslim-majority countries look to local moon sighters, according to Al Jazeera.

The lunar months last between 29 and 30 days, depending on the sighting of the moon on the 29th night of each month. If the moon is not visible, the month will last 30 days.

What do Muslims do during Ramadan and why?

Ramadan is known as the holy month of fasting, with Muslims abstaining from eating and drinking from sunrise to sunset.

Fasting during the holiday is one of the Five Pillars of Islam, along with the daily prayer, declaration of faith, charity and performing the Hajj pilgrimage in Mecca, Saudi Arabia.

In 2016, according to Al Jazeera, fasting hours around the globe ranged between 11 and 22 hours and in the US, 16 to 18 hours.

The fast is intended to remind Muslims of the suffering of those less fortunate and bring believers closer to God (Allah, in Arabic).

During the month, Muslims also abstain from habits such as smoking, caffeine, sex and gossip; this is seen as a way to both physically and spiritually purify oneself while practicing self-restraint.

Here’s what a day of fasting during Ramadan is like:

Muslims have a predawn meal called the “suhoor.”

Then, they fast all day until sunset.

At sunset, Muslims break their fast with a sip of water and some dates, the way they believe the Prophet Muhammad broke his fast more than a thousand years ago.

After sunset prayers, they gather at event halls, mosques or at home with family and friends in a large feast called “iftar."

How is the end of Ramadan celebrated?

Toward the end of the month, Muslims celebrate Laylat al-Qadr or “the Night of Power/Destiny” — a day observers believe Allah sent the Angel Gabriel to the Prophet Muhammad to reveal the Quran’s first verses.

On this night, which falls on one of the last 10 nights of Ramadan, Muslims practice intense worship as they pray for answers and seek forgiveness for any sins.

To mark the end of Ramadan, determined by the sighting of the moon on the 29th, a 3-day celebration called Eid al-Fitr brings families and friends together in early morning prayers followed by picnics, feasts and fun.

Does every Muslim fast during Ramadan?

According to most interpreters of the Quran, children, the elderly, the ill, pregnant women, women who are nursing or menstruating, and travelers are exempt from fasting.

Some interpreters also consider intense hunger and thirst as well as compulsion (someone threatening another to do something) exceptions.

But as an entirety, whether Muslims fast or not often depends on their ethnicity and country.

Many Muslims in Muslim-majority countries, for example, observe the monthlong fast during Ramadan, according to 2012 data from the Pew Research Center.

In fact, in Saudi Arabia, Muslims and non-Muslims can be fined or jailed for eating in public during the day, according to the Associated Press.

But in the United States and in Europe, many Muslims are accepting of non-observers.

Fiona was born premature in January 2017 and received around-the-clock care. She weighed 29 pounds, which zoo officials said is well below a baby hippo’s typical weight. Hippos can grow to be 3,000 pounds.

There is no need to "dress up" for this day, but if you do, do not wear a sombrero, mariachi suit, serape, fake mustache or anything of the sort if you are not a member of that culture. Those things have historical and cultural significance, and donning them just for a day caricatures and stereotypes people. That's not fun.

Go out and get drunk

There is nothing wrong with drinking in moderation and doing it socially, but responsibility is key. What is the use in celebrating a day if you get sick or can't remember it?

Make English words Spanish by adding an "o" on the end

Not only does it not make any sense, but by doing this, it makes fun of another language and turns it into a joke. The same goes for plays on the holiday name, so no parties or themes like "Cinco de Drinko."

You can make a margarita cupcake or a fun cocktail, or have dinner at a family-owned Mexican restaurant. There are plenty of ways to celebrate Cinco de Mayo without doing any of the three above.

Here are five facts about the Mexican holiday that you can use to
impress your friends:

1) Despite a common misconception, Cinco de Mayo is not Mexico’s
Independence Day. The holiday celebrates the
Battle of Puebla
, where, against all odds, the Mexicans made a stand against an
invading French army in 1862.

2) Cinco de Mayo is celebrated more in the United States than it is
in Mexico, with the exception of the city of Puebla. Mexico holds
more of a celebration on its
Independence Day, September 16,
than it does on Cinco de Mayo.

3) The holiday means big business for the avocado industry. The
California
Avocado Commission
says that Americans consume around 81 million avocados during Cinco
de Mayo.

4) Chandler, Arizona, has a unique way of celebrating Cinco de
Mayo. It hosts a Chihuahua race every year.

5) The 2010 U.S. Census estimates that about 31.8 million U.S.
residents are of Mexican origin. The largest concentration of
Mexican-Americans is in Los Angeles, the city that holds the largest
Cinco de Mayo celebration in the U.S.

There is no need to "dress up" for this day, but if you do, do not wear a sombrero, mariachi suit, serape, fake mustache or anything of the sort if you are not a member of that culture. Those things have historical and cultural significance, and donning them just for a day caricatures and stereotypes people. That's not fun.

Go out and get drunk

There is nothing wrong with drinking in moderation and doing it socially, but responsibility is key. What is the use in celebrating a day if you get sick or can't remember it?

Make English words Spanish by adding an "o" on the end

Not only does it not make any sense, but by doing this, it makes fun of another language and turns it into a joke. The same goes for plays on the holiday name, so no parties or themes like "Cinco de Drinko."

You can make a margarita cupcake or a fun cocktail, or have dinner at a family-owned Mexican restaurant. There are plenty of ways to celebrate Cinco de Mayo without doing any of the three above.

The first Earth Day celebration took place 48 years ago, in 1970, after a devastating oil spill in America brought environmental issues to the forefront of public consciousness. According to the Environmental Protection Agency, 22 million people across the country came out in support of environmental reform.

"That day left a permanent impact on the politics of America," Gaylord Nelson wrote in the April 1980 edition of the EPA Journal. "It forcibly thrust the issue of environmental quality and resources conservation into the political dialogue of the nation.

"It showed political and opinion leadership of the country that the people cared, that they were ready for political action, that the politicians had better get ready, too. In short, Earth Day launched the environmental decade with a bang."

Since then, celebrations have only grown. This year, organizers estimate more than one billion people in 192 countries will participate in events the world over. The day is celebrated each year on April 22.

"Our goals include ending single-use plastics, promoting alternatives to fossil fuel-based materials, promoting 100 percent recycling of plastics, corporate and government accountability and changing human behavior concerning plastics," the Earth Day Network, which partners with tens of thousands of organizations in 192 countries to organize Earth Day events, said on its website.

The organization also said it "will educate millions of people about the health and other risks associated with the use and disposal of plastics, including pollution of our oceans, water, and wildlife, and about the growing body of evidence that decomposing plastics are creating serious global problems."

In Tokyo, thousands of people will attend beach cleanups, concerts, art exhibits, classes and other events coordinated by the Green Room Festival, according to the Earth Day Network. In India's Karnataka state, a "no plastic" event will feature workshops led by "organizations that are champions of environmental sustainability in fields including electric vehicles, solar power and zero-waste living," the network said. Cleanups also were scheduled in Palm Beach, Florida; New York; New Jersey and other locations across the United States and worldwide.

“It is so important in the world today that we feel hopeful and do our part to protect life on Earth," Goodall said. "I am hopeful that this Earth Day Google Doodle will live as a reminder for people across the globe that there is still so much in the world worth fighting for. So much that is beautiful, so many wonderful people working to reverse the harm, to help protect species and their environments. And there are so, so many young people, like those in JGI’s Roots & Shoots program, dedicated to making this a better world. With all of us working together, I am hopeful that it is not too late to turn things around, if we all do our part for this beautiful planet.”

Apple also joined in on the celebrations, announcing on April 19 that "for every device received at Apple stores and apple.com through the Apple GiveBack program from now through April 30, the company will make a donation to the nonprofit Conservation International."

“At Apple, we’re constantly working toward smart solutions to address climate change and conserve our planet’s precious resources,” Lisa Jackson, Apple’s vice president of environment, policy and social Initiatives, said in a statement. “In recognition of Earth Day, we are making it as simple as possible for our customers to recycle devices and do something good for the planet through Apple GiveBack. We’re also thrilled to introduce Daisy to the world, as she represents what’s possible when innovation and conservation meet.”

1. Make a PB&J. (Yes, this one is pretty obvious.) According to the New York Daily News, a 2016 survey by Peter Pan Simply Ground Peanut Butter found that the average American will eat nearly 3,000 peanut butter and jelly sandwiches during his or her lifetime. Read more here.

2. Try something a little more adventurous. Is the traditional PB&J not really your thing? If you’re feeling brave, check out this recipe for Spicy Peanut Butter & Jelly Ramen:

3. Eat like the “King.” According to Elaine Dundy's book "Elvis and Gladys," Elvis Presley would eat "sandwich after sandwich of his favorite – peanut butter, sliced bananas and crisp bacon." Get the book here.

5. Help us settle the great debate. Which style of peanut butter better – crunchy or creamy? "Women and children prefer creamy, while most men opt for chunky," the National Peanut Board says on its website. There's also a geographic divide: East Coast residents tend to like smooth peanut butter, while West Coasters like theirs crunchy, according to the site.

One answer is that at the time of Jesus’ crucifixion, “good” may have referred to “holy” in Old English, a linguistic theory supported by many language experts.

According to Slate, the Oxford English Dictionary notes the Wednesday before Easter was once called “Good Wednesday.” Today, it’s more commonly known as Holy Wednesday.

And Anatoly Liberman, a University of Minnesota professor who studies the origins of English words, told Slate if we consider the alternative names for Good Friday, such as “Sacred Friday” (romance languages) or “Passion Friday” (Russian), this theory makes a lot of sense.

Another possible reason for its moniker — a theory supported by both linguists and historical evidence — refers to the holiday’s ties to Easter Sunday, which celebrates the resurrection of Christ.

Because Jesus couldn’t have been resurrected without dying, the day of his death is, in a sense, “good.”

“That terrible Friday has been called Good Friday because it led to the Resurrection of Jesus and his victory over death and sin and the celebration of Easter, the very pinnacle of Christian celebrations,” the Huffington Post reported.

A third answer, some believe, is that the “good” in Good Friday was derived from "God” or “God’s Friday” — the way the term “goodbye” comes from a contraction of the phrase “God Be With You.”

Still, not everyone refers to this day as Good Friday. For example,

The Catholic Encyclopedia mentions that, in the Greek Church, the holiday is known as "the Holy and Great Friday." In German, it's referred to as "Sorrowful Friday."

And as aforementioned, “Sacred Friday” and “Passion Friday” are also used.

In addition, because the holiday is also commemorated with a long fast, Good Friday was also referred to as “Long Friday” by the Anglo-Saxons.